The invention relates to a surgical instrument for the retention of tissue, having at least one valve held on one side.
Instruments of this type are used, for example, in operations to open wounds and hold back organs so that operation routes can be opened up. Valves of this type normally consist of metal, and they are thus impermeable to X-rays. When an area of operation is X-rayed, the regions covered by the valves of such retaining instruments are a considerable interference since in these regions there is no visibility for X-rays at all.
Attempts have been made to overcome this disadvantage by producing the valves from a material which is transparent to X-rays or to design them to be very thin. In both cases, better possibilities do result for recognizing structures on the X-ray picture despite the valves but, on the other hand, the mechanical stability of these valves is so slight that they can no longer reliably fulfill their function.